John Walker knows why no one has broken four minutes for the mile at age 40. "I just don't believe people have been stupid enough to stay around at a high-level competitive edge at 40," he says. "If you'd told me 15 years ago that I'd be trying to do it, I'd have said, Don't be stupid. It's impossible. Absolutely impossible. I didn't think I could run this long. I never intended to run this long. This is by chance."

Walker turns 40 on Jan. 12. Barring injury or a catastrophic decline in his powers, the sturdy New Zealander seems certain to become the first miler to break four minutes at age 40. "If someone else wants to be first," says Rod Dixon, 41, Walker's fellow New Zealander and longtime friend, "he'd better do it before January 12."

That's when "A Night of Miling" is planned for Walker's home track in Auckland's Mount Smart Stadium. Mile races for men and women of all ages will lead up to the evening's featured event—Walker's attempt to do at 40 what was considered humanly impossible at any age until 1954, when Roger Bannister proved otherwise. The race will feature Walker and a field of other runners, all thought capable of breaking four minutes. It will be televised live in New Zealand, and via tape delay in the U.S. and elsewhere. New Zealand Prime Minister Jim Bolger is expected to attend, as are Walker's special guests: Bannister, now 62; Steve Cram, 31, who holds the current mile world record of 3:46.32; and former record holders Herb Elliott, 53; John Landy, 61; Peter Snell, 53; Jim Ryun, 44; and Filbert Bayi, 38.

The world mile record for men 40 and over belongs to Wilson Waigwa of Kenya, who ran 4:05.39 in 1989, four months after he turned 40. "There's a big difference between 4:05 and 4:00," says Walker. "Damn big difference. We're talking about 40 meters. I get amused when I hear about people taking five years off and expecting to come back and break four minutes. There's no way you can."

That was why it was odd when last winter, for the first time in his career, Walker decided against running on the circuit in Australia and New Zealand. He was 15 pounds overweight on his 39th birthday and was set back even further over the next six months. First a lingering flu and then a pull in his right Achilles tendon wiped out his hopes of competing on the European summer circuit. Walker, who had run no slower than 3:56.4 in any year since 1973, the year he broke four minutes for the first time, has not run a single mile on the track in 1991.

"I'm not as good as I used to be," he says. "I've changed. My stride length's probably half of what it was. I probably haven't got the same desire. But I'm still pretty bloody competitive on the track."

Walker's dark blond hair is shaggy. His face is broad and bony. He does not smile readily. "He has a tough exterior, like a hermit crab," says U.S. miler Steve Scott, 35, who has been one of Walker's closest friends and fiercest rivals for years. "Once you break through it, though, he's extremely kind."

Walker is the person to whom the current crop of top milers brings their training diaries. Marcus O'Sullivan, Jim Spivey, Frank O'Mara and Joe Falcon all have sought Walker's advice over the past few years. "Everybody considers John a sort of father figure," says O'Mara, who was 16 when Walker won the 1,500 at the Montreal Olympics in 1976.

He is also their favorite subject of conversation. Walker has always been able to flout the rules without paying for it. "He's not the model you'd show to an aspiring runner," says O'Mara. "He doesn't stretch, he doesn't warm up, and he's been carrying too much weight for too long. While most athletes watch themselves if they're going to be doing intervals, John will go out and work on his farm. He doesn't do the things a world-class runner is supposed to do. The only thing you'd want to emulate about John is his results."

"John Walker is, without question, the greatest miler at achieving firsts," says Falcon. "First to break 3:50. First to run 100 sub-fours. He pioneers everything."

A forthright iconoclast, Walker can be blunt with people; he favors the unvarnished truth. "It's so refreshing talking to someone who actually has strong opinions," says Craig Masback, 36, a former 3:52 miler who is now a TV commentator.

Flexibility? "I have none at all," Walker says. "I'm hopeless. I tried stretching for a year and got injured."

The shoe business? "I see gimmicks in running shoes today that are absolute crap," he says. "You know they're not going to work. They're just a gimmick to sell the shoe, like a spoiler on a car or some fancy stuff on a boat. Basically, all you want is a hull that's not going to sink."

The expiring U.S. indoor circuit? "I think TAC, with all its money, should come to the party and say, Look, for the good of track and field, we're going to prop it up until we get a sponsor, and we're going to make sure it gets on national TV, because, sure as hell, Mr. Network, if you don't take it, you're not going to get the next Olympics."

Walker lives on a 10-acre horse-and-cattle farm a few miles south of Auckland with his wife, Helen, and their three children, Elizabeth, 12, Richard, 8, and Timothy, 3. In January, at the height of the New Zealand summer, pink bougainvillea form a brilliant canopy over the front porch. A tangled heap of running shoes lies on the porch, as if an entire cross-country team had been invited in for lunch.

Walker, barefoot and dressed in faded jeans and a pink T-shirt, leads the way into a living room that contains few mementos of his running career. He owns only a single copy of his autobiography, John Walker, Champion (co-written in 1984 by Ron Palenski), and he has trouble finding it. "I've never read it to this day," he says. "I don't read Track & Field News or other running magazines. We don't talk about running in our house. There are no trophies or pictures of me running. I think that's why I've stayed in the sport so long."

Walker owns another 56 acres 13 miles away, where he grazes 65 head of cattle. He often has Helen drive him to the other pasture and leave him there with nothing but his running gear, so he is forced to run home.

"I just haven't got idle time," he explains over lunch at an Auckland hotel. "This morning we did the horses at eight o'clock. The blacksmith arrived at half past nine to shoe them for the sales next week. Then I came here. While I'm away, my wife is washing the horses. They'll be beautiful and clean when I get home. This afternoon I've got to go out and shift the cattle, and the horses have to be done again. If I hadn't been coming here, there's a big cattle sale today, and I would have been there."

The farm is not a large operation. Walker never has more than four or five thoroughbreds. "That's about all we can handle, Helen and I, without outside help," he explains. One of his horses, a 3-year-old colt named Running John, has finished in the money in 12 of 14 races so far. "His destiny is very exciting," says Walker.

Walker would much rather talk about horses than running. "They get hosed down and put back in a little box, 12 feet by 12 feet. Twenty-three hours later they're taken out to run again. Even if they don't want to run, they still have to. No one praises them for winning. They get a carrot, maybe feed if they're lucky. They get accused and abused when they lose. An athlete gets praised, he gets publicity, he gets rewards."

Walker has been fortunate, and he knows it. "John has had a hard sort of life," says Arch Jelley, the Auckland schoolmaster who has been Walker's coach for the past 20 years. "He left school at 17 and had to fend for himself in odd jobs."

In 1974, the first of his three straight years as the world's top miler, Walker worked at a rock quarry in Auckland. "I was hired to work in the office," he says, "but I ended up a jack-of-all-trades. I drove trucks and did whatever was needed." He worked from seven to five, Monday through Friday and five hours more on Saturday, making NZ$26 ($18 U.S.) a week and shoehorning his training in wherever he could.

"I'd either run to work at six in the morning or I'd run from 11 to 12," Walker says. "Half of that was my lunch hour, and half of it was unpaid time. I used to run as hard as I possibly could within that hour. I'd run 10 miles religiously every day, in 53 or 54 minutes. Then I still had six minutes left to shower and get a bite to eat."

Those days are never far from Walker's mind. His rising fortunes have created a strong sense of obligation. "He'll stand there for hours, signing autographs and doing his bit to promote the sport," says Andy Norman, the powerful British meet promoter. "He doesn't run for the money. He runs because he loves the sport."

In the mid-'70s no group cut a more romantic figure on the European circuit than Walker and the exuberant band of Kiwis he traveled with. "They were like gods," says Scott, "with their long blond hair and beads, dressed in those all-black uniforms."

Walker would arrive in Europe after nine months of solitary preparation on the other side of the earth, intent, it seemed, on cramming all the life he could into those few summer months. He raced, traveled and caroused with a gusto that the cautious professionals of today wouldn't dream of. In 1975, at the end of an exhausting tour of Europe, Walker ran 3:53.62 one evening in London, then stayed out all night at a party. He got two hours sleep, flew to Sweden and took a shot at the world 2,000 record.

"Missed it by half a second," he says. "That was pretty dumb. But that was the way we were then. We just didn't know what we were doing. We trained hard, we raced hard, we dominated. If I knew then what I know now, I probably would have been more selective in my races. But it didn't matter, because we beat everyone anyway.

"I never set out to run miles," says Walker, who has, nevertheless, run 129 of them in under four minutes. He adds, "I've probably run 400 1,500's at an equivalent pace."

Of those 129 sub-four-minute miles:

•His first, a 3:58.8, came on July 7, 1973, in Victoria, B.C., when Walker was 21.

•The historic 3:49.4—the first mile under 3:50-came on Aug. 12, 1975, in G‚Äö√†√∂‚Äö√†√áteborg, Sweden. It was only Walker's 11th sub-four race, and the photo of him crossing the finish line is one of the most famous in track and field. In the photo Walker, his mouth agape and his head thrown back in agony, looks as though he had run smack into an invisible force field. Seven years passed before he lowered his best again, running 3:49.08 when he was 30 in a race won by Scott in Oslo. He is still history's eighth-fastest miler.

•Twenty-one of the miles were run indoors; two were on grass tracks outdoors.

•The oddest of the lot, in Walker's opinion, was the mile he lost to Eamonn Coghlan in Tullylease, Ireland, in 1981. "The meet was organized by a priest," recalls Walker. "He redirected traffic so that every road in the area led to the track. Then he charged people a pound whether they wanted to come or not. Only in Ireland."

•He ran his 100th, a 3:54.57, on Feb. 17, 1985, at Mount Smart Stadium. The circumstances surrounding that race say a great deal about Walker's hunger to reach milestones. Scott, another prodigious miler with 96 sub-fours to his credit at the time, had proposed that, to heighten the drama and generate publicity for the sport, Walker wait until Scott reached 99 too and that they go for their 100th in the same race. Though he regards Scott with deep respect and affection, Walker refused.

"All that counts is who's first," Walker says, without a hint of apology. "That's why I couldn't share Steve's sentiments, standing around waiting for him to come along. No one cares who's second."

Scott, it must be noted, has since passed Walker, with 141.

As amazing as it is that a 40-year-old might run under four minutes, it is doubly amazing that it is Walker who has lasted this long. At the Montreal Olympics in '76, Graeme Campbell, New Zealand's team doctor, took Jelley aside. "He told me that John's Achilles tendon was so fragile that he couldn't see it lasting another season," says Jelley.

Nor was the Achilles Walker's only injury. Shortly before the Games, he had developed a mysterious ailment in his right leg. Exactly 30 minutes into a run, no matter at what pace he was going, the leg would go numb, and he would have to stop. "It was like an alarm had gone off," he says. "It felt as if a giant hand had grabbed it and was twisting."

Jelley, ever resourceful, worked around the injury. "What he'd do," says Walker, "was take me up to the Waitakere Ranges, the mountains where Snell used to run. There's a hill there that's two and a half miles long and a real gut buster. I used to flog myself right from the bottom to the top of it as fast as I possibly could. That took 15 minutes. Then he'd put me in the car and run me down and I'd do it again. That was the hardest training you could do. You wouldn't normally do that training. You just wouldn't attempt it." In 1977, with this as the staple of his training, Walker ran 1,500 meters in 3:32.7, fastest in the world that year.

Walker visited 30 doctors in 2½ years before the problem was finally diagnosed as "muscle entrapment," a condition in which the calf muscle expands, cutting off the flow of blood through the artery. "They cut me from one end [of my calf] to the other," says Walker. It took 160 stitches to sew him back up. In the summer of 1979, when Walker came back, he had changed tremendously.

"He had been arrogant, definitely, and he'd admit it, too," says Scott. "He was unbearable, impolite and real quick with people up until 1977, when he was beaten by Steve Ovett in the World Cup. He missed most of '78, and when he came back, he was much more humble."

Walker does not expect to compete much beyond his 40th birthday. He anticipates a contented retirement but knows there are some things about the track world that he will miss. "You run your race, you go and have a beer afterward," he says. "I have not met, in my 30 years in the sport, many bad people in track and field, people I would not like to sit down and have a meal with. Of the thousands of athletes I've met, I think they are all a pretty good bunch."

The feeling is mutual. Happy birthday, John.

PHOTOHEINZ KLUETMEIER

In New Zealand, Walker's feat seems made in the shade.

PHOTOJAMES DRAKE

The agony of ecstasy: Walker won the '76 Olympic 1,500 (above) and shattered the mile mark in '75.

PHOTOAP

[See caption above.]

PHOTOHEINZ KLUETMEIER

The good life is down on the farm for John, Helen and their brood (from left): Richard, Timothy and Jan.